Mercedes 2.1 CDI (OM651) Chip Tuning: Delphi CRD3 and Bosch EDC17C66 on C 220, E 250, Vito
The 2.1 litre OM651 has been Mercedes’ most used diesel for more than a decade: C 200 / 220 / 250 CDI, E 220 / 250 CDI, GLK, Vito and Sprinter. Depending on injector type the ECU is the Delphi CRD2 / CRD3 or the Bosch EDC17C66. Files from Stage 1 to emission solutions are available at ECU Prime on these ECUs.
Which ECU does the OM651 use?
- Delphi CRD3: Stage 1, Stage 2, Stage 3, AdBlue / SCR, DPF, EGR, lambda, swirl (TVA), emission package; combined Stage 1 + DPF + EGR, start-stop off.
- Delphi CRD2 and CRD.11: Stage 1, Stage 2, AdBlue / SCR, DPF, EGR and emission package.
- Bosch EDC17C66: Euro 6 OM651. Stage 1, Stage 2, AdBlue / SCR, DPF, EGR; combined Stage 1 + EGR + AdBlue.
For the new 2.0 litre OM654 (C 200 d, E 220 d) see our Bosch MD1CP001 article. Engine pages: C 220 CDI Stage 1, C 250 CDI Stage 1. Models: C-Class, E-Class, GLK, Vito and Sprinter.
The ECU type depends on model year and engine. The exact type is confirmed from the ECU label or by reading it with a diagnostic tool; send a photo of the label on WhatsApp and we will tell you which file applies.
Common faults
- DPF loading and endless regeneration in city driving
- Sooted EGR valve and cooler, loss of pulling power
- AdBlue / SCR warning and NOx sensor failure
- Boost pressure fault and limp mode
Service pages: Mercedes AdBlue fault solution, DPF fault solution, EGR fault solution.
How it works
- Reading: upload the original file read with your tool, or visit one of our locations.
- Calibration: the file is prepared for the exact engine and ECU software version, checksum corrected; the original is archived.
- Application and check: fault scan and run / road test after writing.
Workshops get the same solutions through the ECU Prime file service.
Emission-related software is offered only for uses permitted by applicable law (off-road / closed-site use, racing, export, diagnostics); road use and inspection compliance are the owner’s responsibility.